1. Field of the Invention
The present invention relates generally to a bush assembly used for fixing an elongated member to a stationary base. More specifically, the invention relates to a bush assembly or a slipping bush which can be used for fixing the upper arm of a double wishbone type suspension to a vehicular body.
2. Description of the Prior Art
As is well known, the upper arm of a double wishbone type suspension is oscillatably fixed to a vehicle body by means of a bush assembly. Such a bush assembly generally comprises an inner cylindrical member, an outer cylindrical member arranged so that the axis thereof coincides with that of the inner cylindrical member, and a rigid sleeve arranged therebetween. The rigid sleeve is fixed to the inner surface of the outer cylindrical member by means of an elastic member, and slidably engages the outer surface of the inner cylindrical member via a slipping member.
The upper arm is provided with a holding portion which has an essentially cylindrical through opening in which the outer cylindrical member is fixed. A supporting pin is inserted into the inner cylindrical member and is connected to the vehicle body, so that the wheel can be connected to the vehicle body.
In such a bush assembly, since the outer cylindrical member and the holding portion are made of a metal, if muddy water or the like gets into the interface between the outer metallic member 14 and the through opening of the holding portion from the outside, the bush assembly tends to corrode, so that durability of the bush assembly is decreased.
In order to eliminate the aforementioned disadvantages, i.e. to prevent muddy water or the like from getting the interface, the U.S. Pat. No. 3,526,413 to Alf John Muller et al, filed on Feb. 14, 1968, discloses a bush assembly which does not have any outer cylindrical metallic member, and in which the outer surface of the elastic member is directly fixed in the through opening of the holding portion.
However, it is difficult to insert this bush assembly into the through opening of the holding portion, since it does not have any outer cylindrical member, i.e. an elastic member is arranged on the outside.